Objective: The purpose of this study was to investigate the efficacy of an experimental dentin conditioner consisting of ascorbic acid (AA) and ferric chloride (Fe) on micro-tensile bond strength (µTBS). Methods: Three exprimental aqueous conditioners including 10 wt% AA and 5 wt% Fe (10AA-5Fe), 10 wt% AA without Fe (10AA-0Fe), 5 wt% Fe without AA (0AA-5Fe)] were prepared. One commercial conditioniner, Green conditioner [(10% citric acid and 3% ferric chroride (10CA-3Fe), Sun Medical)] was also used as a control. The coronal surfaces of extracted human molars were ground flat to dentin with #320 SiC paper under irrigation. The surfaces were treated with each experimental solution. Resin composite rods (Clearfil AP-X, Kuraray) were bonded to the dentin surfaces with a self-curing resin (Super-Bond C&B, Sun Medical). A commercially available adhesive system (10CA-3Fe/Super-Bond C&B) was used as a control. After 24-h immersion in 37 ˚C distilled water, 0.9x0.9 composite-dentin beams prepared from the luted specimens were stressed to failure in tension at 0.6 mm/min. The data were analyzed by one-way ANOVA and Duncan new multiple range test (n=13, p<0.05). Results: The group 10AA-5Fe showed significantly higher bond strength compared to the groups 10AA-0Fe, 0AA-5Fe, 0AA-0Fe, and 10CA-3Fe (Table below).
Table Results of tensile bond strengths: Mean value and (standard deviation) Unit: MPa
| Conditioner | 10AA-5Fe | 10AA-0Fe | 0AA-5Fe | 0AA-0Fe | 10CA-3Fe |
| µTBS | 33.2(8.3) | 10.5(3.2)a | 8.7 (2.2)a | 5.8(1.7)a | 25.6(8.5) |
Values with identical superscript letter indicate no significant difference (p>0.05).
Conclusion: It was concluded that the experimental conditioner consisting of 10% ascorbic acid and 5% ferric chloride improved the bonding between Super-Bond C&B resin and dentin compared to Super-Bond system.